1. Field of the Invention
The present invention relates to a photoresist stripping composition containing the combination of (1) selected solvents; (2) alkanolamines; and (3) a selected corrosion inhibitor.
2. Description of the Prior Art
The photoresist stripper art is replete with numerous references to stripper compositions containing both a polar solvent and an amine compound. The presence of an amine in photoresist stripper compositions has been judged to be essential to effectively remove cross-linked resist films. However, amine-type photoresist strippers sometimes have a serious problem of corrosion, especially with aluminum substrates.
It is believed that the corrosion is caused in part by the ionization of water with the amine in post-stripping water rinse, as residual stripper solution may be retained on the substrate surface and/or substrate carrier after the stripping step. In other words, the amine component of the stripper composition does not corrode the substrate by itself, but can trigger water to cause the corrosion.
To solve this problem, an intermediate rinse step with an organic solvent has been used between the stripping step and the post-stripping rinse with water. For example, isopropyl alcohol solutions have been used for this purpose. However, such intermediate rinses are not necessarily desirable because overall stripping operation becomes more complicated and, furthermore, an additional solvent waste is produced. Accordingly, if amine-type strippers are to be further employed, there is a need to solve this corrosion problem without intermediate organic solvent wastes. The present invention provides such a solution.
Illustrative of references suggesting photoresist stripper compositions containing the combination of a polar solvent and an amine compound are the following:
1. U.S. Pat. No. 4,617,251, which issued to Sizensky et al. (Olin Hunt) on Oct. 14, 1986, teaches a positive photoresist stripping composition containing (A) selected amine compound (e.g., 2-(2-aminoethoxy)-ethanol; 2-(2-aminoethylamino)-ethanol; and mixtures thereof) and (B) selected polar solvents (e.g., N-methyl-2-pyrolidinone, tetrahydrofurfuryl alcohol, isophorone, dimethyl sulfoxide, dimethyl adipate, dimethyl glutarate, sulfolane, gamma-butyrolactone, N,N-dimethylacetamide and mixtures thereof). The reference further teaches that water as well as dyes or colorants, wetting agents, surfactants and antifoamers may be added into this composition. PA1 2. U.S. Pat. No. 4,770,713, which issued to Ward (J. T. Baker) on Sep. 13, 1988, teaches a positive photoresist stripping composition containing (A) a selected amide (e.g., N,N-dimethyl acetamide; N-methyl acetamide; N,N-diethyl acetamide; N,N-dipropyl acetamide; N,N-dimethyl propionamide; N, N-diethyl butyramide and N-methyl-N-ethyl propionamide) and (B) selected amine compound (e.g., monoethanolamine, monopropanolamine, methyl-aminoethanol). The patent also teaches this stripper may optionally contain a water miscible nonionic detergent (e.g., alkylene oxide condensates, amides and semi-polar nonionics). PA1 3. U.S. Pat. No. 4,824,763, which issued to Lee (EKC) on Apr. 25, 1989, teaches positive-working photoresist stripping composition containing (A) triamine (e.g., diethylene-triamine) and (B) a polar solvent (e.g., N-methyl-2-pyrrolidone, dimethylformamide, butyrolactone, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons). PA1 4. U.S. Pat. No. 4,904,571, which issued to Miyashita et al. on Feb. 27, 1990, teaches printed circuit board photoresist stripper composition containing (A) a solvent (e.g., water, alcohols, ethers, ketones, chlorinated hydrocarbons and aromatic hydrocarbons); (B) an alkaline compound dissolved in said solvent (e.g., primary amines, secondary amines, tertiary amines, cyclic amines, polyamines, quaternary ammonium amines, sulfonium hydroxides, alkali hydroxides, alkali carbonates, alkali phosphates and alkali pyrophosphates); and (C) a borohydride compound dissolved in said solvent (e.g., sodium borohydride, lithium borohydride, dimethyl amine borone, trimethyl amine borone, pyridane borone, tert-butyl amine borone, triethyl amine borone, and morpholine borone). PA1 5. U.S. Pat. No. 5,102,777, which issued to Lin, et al. on Apr. 7, 1992, teaches a positive photoresist stripper composition comprising (A) a solvent (e.g., a pyrrolidone compound, a diethylene glycol monoalkyl ether, a sulfur oxide compound, a sulfolane compound or a mixture thereof); (B) an amine (e.g., alkanolamine); and (C) a fatty acid (e.g., capric acid, lauric acid, talmitric acid, caprylic acid, myristic acid, oleic acid, stearic acid, linoleic acid, linolic acid, buthylic acid, abietic acid, isooctoic acid, isohexadecanoic acid, isostearic acid, behenic acid, undecylenic acid, hydroxystearic acid, chipanodonic acid, arachidonic acid, oleostearic acid, and 2-ethylhexadecanilic acid). PA1 6. U.S. Pat. No. 5,279,791, which issued to Lee (EKC) on Jan. 18, 1994, teaches a stripping composition for removing resists from substrates containing (A) hydroxylamine (e.g., NH.sub.2 OH); (B) at least one alkanolamine; and optionally (C) at least one polar solvent. PA1 7. U.S. Pat. No. 5,308,745, which issued to Schwartzkopf on May 3, 1994, teaches an alkaline-containing photoresist stripping composition comprising (A) a stripping solvent (e.g., 2-pyrrolidinone, 1-methyl-2-pyrrolidinone, 1-ethyl-2-pyrrolidinone, 1-propyl-2-pyrrolidinone, 1-hydroxyethyl-2-pyrolidinone, 1-hydroxypropyl-2-pyrrolidinone, diethylene glycol monoalkyl ethers, dialkyl sulfones, dimethyl sulfoxide, tetrahydrothiophene-1,1-dioxides, polyethylene glycol, dimethylacetamide and dimethylformamide; (B) a nucleophilic amine (e.g., 1-amino-2-propanol, 2-(2-aminoethoxy)ethanol, 2-aminoethanol, 2-(2-aminoethylamino)-ethanol and 2-(2-aminoethylamino) ethylamine); and (C) a non-nitrogen containing weak acid (e.g., acetic acid, phthalic acid, 2-mercaptobenzoic acid, 2-mercaptoethanol, 1,3,5-trihydroxybenzene, pyrogallol, resorcinol, 4-tert-butylcatechol, carbonic acid and hydrofluoric acid). PA1 8. U.S. Pat. No. 5,334,332, which issued to Lee (EKC) on Aug. 2, 1994, teaches a photoresist resist stripping and cleaning composition comprising (A) hydroxylamine; (B) at least one alkanolamine; (C) water; (D) optionally, at least one polar solvent; and (E) optionally, a chelating reagent (e.g., thiophenol, ethylenediamine tetraacetic acid and 1,2-dihydroxybenzene) to reduce the surface metal contamination on wafers. PA1 9. U.S. Pat. No. 5,399,464, which issued to Lee on Mar. 21, 1995, teaches a stripping composition for removing positive organic photoresist from a substrate comprising (A) a triamine (e.g., diethylene triamine); (B) a nonpolar or polar organic solvent (e.g., N-methyl pyrrolidone). PA1 10. U.S. Pat. No. 5,417,802, which issued to Oberg on May 23, 1995, teaches a material useful for photoresist removal or post-metal etch clean up that comprises (A) primary or secondary amines; (B) solvents (e.g., dimethyl sulphoxide or dimethylacetylamide); and (C) organic ligands such as crown ethers or cyclodextrines). PA1 11. U.S. Pat. No. 5,472,830, which issued to Honda on Dec. 5, 1995, teaches a non-corrosion photoresist stripping composition comprising (A) an organic polar solvent; (B) an amine compound; (C) selected amino acid; and (D) optionally, water. PA1 12. German Published Patent Application No. DE3828513, which issued to Schulz (Merck) on Mar. 1, 1990, teaches a positive and negative photoresist stripper composition containing (A) an aprotic polar solvent (e.g., 1,3-dimethyl-2-imidazolidinone or 1,3-dimethyl-tetrahydro-pyrimidinone); and (B) an organic base (e.g., alkanolamine). PA1 13. European Patent Application No. 647,884, which was published on Apr. 12, 1995, teaches an alkaline photoresist stripping composition comprising (A) an organic solvent system; (B) amines; and (C) reducing agents (e.g., ascorbic acid, uric acid, butyne diols, unsaturated ketones, tetramisole, hydrazine and its derivatives, oximes, hydroquinone, pyrogallol, gallic acid and alkyl esters thereof, tocopherol, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, butylated hydroxytoluene, butylated hydroxyanisole, 2,6-di-tert-butyl-4-hydroxymethylphenol, thiols, aldehydes and derivatives thereof). PA1 14. Japanese Published Patent Application No. 56-115368, which was published on Sep. 10, 1981 and is assigned to San Ei Chemical Industries, KK, teaches a photoresist stripping composition containing (A) nonionic surface activator (e.g., a polyethylene glycol ether); (B) organic solvent (e.g., cyclohexanone); and (C) either a swelling agent (e.g., polyethylene glycol) or penetrant (e.g., 2-aminoethanol). PA1 15. Japanese Published Patent Application No. 63-208043, which was published to R. Ohtani (Kanto Chemical) on Aug. 29, 1988, teaches a positive-working photoresist stripper composition containing (A) 1,3-dimethyl-2-imidazolidinone; (B) a water-soluble organic amine [e.g., monoethanolamine, 2-(2-aminoethoxy)-ethanol, triethylene(tetramine)]. The application also teaches a surfactant may be added to the stripper. PA1 16. Japanese Published Patent Application No. 64-081949, which was published to K. Matsumoto (Asahi Chemical) on Mar. 28, 1989, teaches a positive-working photoresist stripper composition containing (A) a solvent (e.g., gamma-butyrolactone, N-methyl-formamide, N,N-dimethylformamide, N,N-dimethyl-acetamide or N-methylpyrrolidone); (B) an amino alcohol (e.g., N-butyl-ethanolamine and N-ethyldiethanolamine); and (C) water. PA1 17. Japanese Published Patent Application No. 64-088548, which was published to S. Shiotsu (Nagase Denshi Kagaku) on Apr. 3, 1989, teaches a photoresist stripping composition comprising (A) monoethanol amine; (B) glycol monoalkyl ether; (C) water; and (D) optionally, 2-butyne-1,4-diol as a corrosion inhibitor for a positive photoresist stripper. PA1 18. Japanese Published Patent Application No. 4-124668, which was published to K. Wakiya (Tokyo Ohka) on Apr. 24, 1992, teaches a less corrosive photo resist stripping agent comprising (A) an organic amine; (B) a glycol monoalkyl ether solvent; (C) 2-butyne-1,4-diol; and (D) a phosphoric acid ester surfactant. PA1 19. Japanese Published Patent Application No. 4-350660, which was published to H. Goto (Texas Instruments, Japan and Kanto Chemical, Inc.) on Dec. 4, 1992, teaches a stripper for positive photoresists comprising (A) 1,3-dimethyl-2-imidazolidinone (DMI), (B) dimethylsulfoxide (DMSO) and (C) a water-soluble amine [e.g., monoethanolamine or 2-(2-amino-ethoxy)ethanol] wherein the amount of the water-soluble amine is 7-30% by weight. PA1 20. Japanese Published Patent Application No. 5-045894, which issued to Ward (ACT, Inc.) on Feb. 26, 1993, teaches the use of 6-hydroxy-quinoline as a corrosion inhibitor in a positive photoresist stripper. PA1 21. Japanese Published Patent Application No. 7-028254, which published to Kanto Kagaku KK on Jan. 31, 1995, teaches photoresist stripper composition comprising (1) a sugar-alcohol (e.g., D-sorbitol), isopropyl alcohol, dimethyl sulphoxide, or 1,3-dimethyl-2-imidazolidinone; (2) an alkanolamine; (3) water; and (4) quaternary ammonium hydroxide. PA1 22. Japanese Published Patent Application No. 7-271056, which was published to K. Adachi, et al. (Mitsubishi Gas Chemical), teaches a stripping and cleaning agent for removing dry-etching photoresist residues from a semiconductor substrate comprising (A) an organocarboxylic ammonium salt or an amine carboxylate; and (B) a fluorine compound. PA1 (a) from about 20 to about 70% by weight of an organic polar solvent having a dipole moment of more than 3.5; PA1 (b) from about 70 to about 20% by weight of an alkanolamine compound; and PA1 (c) from about 0.1 to about 10% by weight of 2,2'-[[(methyl-1H-benzothiazol-1-yl)methyl]imino]bis-ethanol. PA1 (a) a polar solvent having a dipole moment of more than 3.5; PA1 (b) an alkanolamine; and PA1 (c) 2,2'-[[(methyl-1H-benzothiazol-1-yl)methyl]imino]bis-ethanol. PA1 (a) excellent prevention of various different types of the metal corrosion of substrate surfaces; PA1 (b) favorable material cost for the desired corrosion inhibition effect.
None of these references suggest the addition of the selected corrosion inhibitor disclosed in this invention to a mixture of selected solvents and selected amines for application to the photoresist stripping.